Pfizer has announced positive overall survival (OS) results from a late-stage study of its prostate cancer combination treatment.
The phase 3 TALAPRO-2 trial has been evaluating the drugmaker’s PARP inhibitor Talzenna (talazoparib) in combination with its Astellas-partnered androgen receptor pathway inhibitor (ARPI) Xtandi (enzalutamide) in patients with metastatic castration-resistant prostate cancer (mCRPC).
Results showed a statistically significant and clinically meaningful OS improvement for patients receiving the combination in the ‘all-comers’ cohort, as well as those with homologous recombination repair (HRR) gene-mutated mCRPC, compared to Xtandi alone.
Talzenna plus Xtandi is now the first and only PARP inhibitor/ARPI combination to significantly improve survival in mCRPC patients regardless of mutation status, noted Roger Dansey, Pfizer’s chief development officer, oncology.
The clinically meaningful improvement in radiographic progression-free survival from the prior primary analysis of the trial was also maintained in both cohorts, and the safety profile of the combination was generally consistent with the known safety profile of each drug.
Prostate cancer is the second most common cancer in men worldwide, with an estimated 1.4 million new cases diagnosed in 2022.
Up to 20% of patients develop mCRPC, a form of the disease that has spread beyond the prostate gland and has progressed despite medical or surgical treatment to lower testosterone, within five to seven years of diagnosis.
Talzenna plus Xtandi was approved by the US Food and Drug Administration in June 2023 for use in adults with HRR gene-mutated mCRPC. The combination was also approved by the European Commission in January 2024 to treat mCRPC in adults for whom chemotherapy is not clinically indicated.
The new data from TALAPRO-2 will now be shared with global health authorities to support potential label expansion.
Global lead investigator for the trial Neeraj Agarwal, Huntsman Cancer Institute, University of Utah, said: “These OS results indicate potentially practice-changing efficacy for Talzenna in combination with Xtandi for men with mCRPC.
“mCRPC is the most advanced and aggressive stage of the disease, and the TALAPRO-2 results provide much-needed hope to patients who remain in high unmet need for effective treatment options.”